When deleting an item (feature from a part, a component part or sub-assembly from an assembly and a drawing view from a drawing) you will be asked to confirm the deletion.
You have the option to check Don't show again. I don't check this box (ever), because I want SOLIDWORKS to talk to me. Not checking this is my personal preference.
After checking Don't show again and clicking yes, the item has been deleted.
Upon deleting another item, you will not be asked to confirm the deletion. Where did it go? How do I get it back?
Here is how you can get it back.
Go to Options, Under System Options tab, click Messages/Errors/Warnings. In the Dismissed Message box, you will see "Do you really want to delete the following item(s)?" Check this box and click OK.
Upon deleting another item, you will now be asked to confirm the deletion.
Thanks and have a great day.